Curtain walls are generally used and applied in modern building constructions and are the outer covering of said constructions in which the outer walls are non-structural, but merely keep the weather out and the occupants in. Curtain walls are usually made of a lightweight material, reducing construction costs and weight. When glass is used as the curtain wall, a great advantage is that natural light can penetrate deeper within the building.
Due to the recent developments on the building construction market, unitized panels play an important role when a curtain wall is built-up. The use of unitized panels make installation of a curtain wall easier to the installer, as the pre-assembled curtain wall panel will be quickly installed on the jobsite. Unitized panels are built offsite in a curtain wall manufacturing facility. These unitized panels are then assembled in a controlled manufacturing process and shipped to the construction jobsite where they will be hung on the building. This process is highly desirable since it allows for quick and clean installation of the unitized panel on the jobsite when compared, for example, to the used stick build façade construction. Further, this pre-manufacturing of unitized panels ensures the quality of fire protection that is required according to various standards.
In general, a glass curtain wall structure or glass curtain wall construction is defined by an interior wall glass surface including one or more framing members and at least one floor spatially disposed from the interior wall surface. The gap between the floor and the interior wall surface of a curtain wall defines a safing slot, also referred to as perimeter slab edge (void), extending between the interior wall surface of the curtain wall construction and the outer edge of the floor. This safing slot is essential to slow the passage of fire and combustion gases between floors. Therefore, it is of great importance to improve fire stopping at the safing slot in order to keep heat, smoke and flames from spreading from one floor to an adjacent floor. It is important to note that the firestop at the perimeter slab edge is considered a continuation of the fire-resistance-rating of the floor slab. In general, the standard fire test method NFPA 285 provides a standardized fire test procedure for evaluating the suitability of exterior, non-load bearing wall assemblies and panels used as components of curtain wall assemblies, and that are constructed using combustible materials or that incorporate combustible components for installation on buildings where the exterior walls have to pass the NFPA 285 test.
In order to obtain certified materials, systems and assemblies used for structural fire-resistance and separation of adjacent spaces to safeguard against the spread of fire and smoke within a building and the spread of fire to or from the building, the International Building Code IBC 2012 provides minimum requirements to safeguard the public health, safety and general welfare of the occupants of new and existing buildings and structures. According to the International Building Code IBC 2012 Section 715.4, voids created at the intersection of the exterior curtain wall assemblies and such floor assemblies shall be sealed with an approved system to prevent the interior spread of fire where fire-resistance-rated floor or floor/ceiling assemblies are required. Such systems shall be securely installed and tested in accordance with ASTM E 2307 to provide an F-rating for a time period at least equal to the fire-resistance-rating of the floor assembly.
However, there is a code exception that states that voids created at the intersection of the exterior curtain wall assemblies and such floor assemblies, where the vision glass extends to the finished floor level, shall be permitted to be sealed with an approved material to prevent interior spread of fire. Such material shall be securely installed and capable of preventing the passage of flame and hot gasses sufficient to ignite cotton waste when subjected to ASTM E 119 time-temperature fire conditions under a minimum positive pressure differential of 0.01 inch of water column for the time period at least equal to the fire-resistance-rating of the floor assembly.
Although some glass and frame technologies have been developed that are capable of passing applicable fire test and building code requirements, there is hardly any system that addresses the exception stated in the International Building Code IBC 2012 Section 715.4 and fulfills the code section ASTM E 2307 full-scale testing.
However, there is no system known of which parts can be pre-assembled that addresses above mentioned exception and at the same time complies with the requirements according to ASTM Designation: E 1399-97 (Reapproved 2005), in particular having a movement classification of class IV, when finally installed. Class IV is a combination of thermal, wind, sway and seismic movement types. These have been tested according to the invention in both horizontal and vertical conditions. The E 1399, Standard Test Method for Cyclic Movement and Measuring the Minimum and Maximum Joint Widths of Architectural Joint Systems, is used for simulation of movements of the ground, such as for example an earthquake, or even movements under high wind load or life load. In particular, there is no system known that is used in a curtain wall structure that provides a dynamic system complying with ASTM E 1399, such as for example a curtain wall structure defined by an interior wall surface, which includes an interior panel, such as a back pan, extending over the interior surface thereof and at least one floor spatially disposed from the inner wall surface, thereby sealing of the safing slot between the floor and the back pan of this curtain wall, which extends between the interior wall surface of the interior panel and the outer edge of the floor, in particular when vision glass is employed. Said safing slot is needed to compensate dimensional tolerances of the concreted floor and to allow movement between the floor and the façade element caused by load, such by life, seismic or wind load.
Due to the increasingly strict requirements regarding fire-resistance as well as horizontal and vertical movement, there is a need for a dynamic, thermally and acoustically insulating and sealing system for a curtain wall structure that is capable of meeting or exceeding existing fire test and building code requirements and standards including existing exceptions and which can be easily installed on the jobsite. In particular, there is a need for a pre-manufactured unitized panel, ready to be installed on the jobsite, that prevents in its final installation the spread of fire when vision glass of a curtain wall structure extends to the finished floor level below even when exposed to certain movements (complying with the requirements for a class IV movement).
In view of the above, it is an object of the present invention to provide a process for assembling a unitized panel for use within an exterior dynamic curtain wall assembly, which includes glass, especially vision glass extending to the finished floor level below.
Further, it is an object of the present invention to provide a unitized panel that is full-scale ASTM E 2307 as well as ASTM E 1399 tested, to address the code exception, to avoid letters and engineering judgments, and to secure and provide defined/tested architectural detail for this application, in particular, by providing a tested panel for fire-as well as movement-safe architectural compartmentation and which makes it easier for the installers to build up the curtain wall on the jobsite.
Still further, it is an object of the present invention to provide a process for installing the unitized panel of the invention to improve fire stopping at the safing slot of an exterior dynamic curtain wall assembly.
Still further, it is an object of the present invention to provide at the same time a unitized panel, which is used as an acoustic insulating and sealing system for effectively acoustically insulating and sealing of the safing slot between a curtain wall structure and the edge of a floor.
These and other objectives as they will become apparent from the ensuing description of the invention are solved by the present invention as described in various embodiments. Preferred embodiments further describe the invention.